Merriam-Webster's Collegiate® Dictionary, 11th Edition
FLUFF
I. noun
Etymology: perhaps blend of flue (fluff) and puff
Date: 1790
down VII,1, something fluffy , something inconsequential, blunder ,
II. verb
Date: 1835
transitive verb to make fluffy ,
2. to spoil by a mistake ; botch , to deliver badly or forget (one's lines) in a play, intransitive verb to become fluffy, to make a mistake